Clutch



urv-(U., l ocawunuw Sept. 25, 1945. HUNT 2,385,517

CLUTCH Filed Jan. 19, 1944 2 Sheets-Sheet 1 Zinnentor attorney w m w o aJ a E? \D% wa /6v? i w y a W G. HUNT CLUTCH Filed Jan. 19, 1944 Sept.25, 1945.

Patented Sept. 25, 1945 UNITED STATES PATENT OFFICE CLUTCH George Hunt,Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., acorporation of Delaware Application January 19, 1944, Serial No. 518,811

.6 Claims.

This invention has been made to improve the operation of a clutch of thedouble driven disc type and, while useful in other relations, has beendesigned particularly for heavy vehicles.

The object of the invention is to provide a frictional surface areawhich shall be greater than in the case of the conventional single disctype. Another object is to insure release of all the frictional engagingfaces when the clutch is released. Another and important object is toprovide a simple expedient operating automatically to effect adjustmentfor wear. Other objects will appear as one reads the followingdescription.

On the drawings:

Figure 1 is a transverse section through the clutch.

Figure 2 is a view as seen from line 22 of Figure 1.

Figure 3 is an enlarged detail.

Figure 4 is a sectional view corresponding to a part of Figure l andshowing on a larger scale the position of the parts when the clutch isreleased.

Figure 5 is a similar section showing the position of the parts when theclutch is engaged.

Referring to the drawings, the clutch is shown associated with aconventional flywheel marked I. A cover member 9 is secured to theflywheel by bolts II as usual and forms a clutch housing to enclose theusual pressure plates and driven discs.

The conventional transmission shaft is marked l3. It has a splinedportion l5 to receive slidably two spaced driven disc hubs l1 and I9. Tothe hubs are secured by fastening means 2| driven discs 23, 25 whichcarry on their opposite surfaces friction facings 21. Between the drivendiscs 23 and 25 is a pressure plate 29. This pressure plate has radiallugs 3| which enter cover slots 33 so that the rotation of the flywheeland cover is transmitted to the pressure plate. The pressure plate 29may have radial passages 35 for cooling as is customary. The pressureplate may slide toward and from the flywheel, the lugs 3| traveling onthe slots 33. It will be evident that when the pressure plate 29approaches the flywheel the facings 21 of driven plate 25 frictionallyengage the flywheel face and the face of the pressure plate. A secondpressure plate 31 is also used. It, too, has guiding and driving lugs39. This plate is on that side of driven plate 23 remote from theflywheel and when moved toward the flywheel the facings of driven plate23 are gripped by the adjacent surfaces of the two pressure plates.

The cover 9 serves as the abutment for the clutch engaging spring forwhich I have chosen a coned or Belleville washer type of spring marked4|. This spring when unrestrained by the clutch releasin means fulcrumson a ring surface 43 on the cover and exerts pressure on a similar ringsurface 45 on pressure plate 31. Adjacent the central opening of theconed spring there may be attached at 46 two or more fingers 41 to beengaged by the axially slidable releasing means. The releasing means maybe moved to clutch releasing position, to the right in the drawing, bythe forked ends 49 of a suitable lever, not shown. These ends engageradially projecting parts 5| of a cup-shaped member 53 formed integrallywith a sleeve 55. A cover for the releasing means is marked 51 and thetwo parts 58 and 51. are secured together by bolts 59. Within theenclosure formed parts 53 and 51 is a bearing 60 which is retained by aretainer 6|. Upon the sleeve 55 and projecting into the enclosure is abearin guide 63 to which the retainer is keyed. The guide is threaded toreceive a. nut 65 between which and the retainer BI is a hub 66 forengaging the fingers 51, there being shown a lock washer 61 between thenut and the hub. When the lever ends move the throwout assembly to theright the hub 66 moves the inner region of the spring 4| to the right.Its pressure on pressure plate 31 is relieved.

To the pressure plate 31 are secured bolts 69 projecting out throughopenings in the spring plate as shown. Under the heads of these boltsare yielding spring members H engaging the spring plate. As the springplate is pulled off the pressure plate the movement of the spring plateeffects, through parts H and 69, a movement of the pressure plate 31 tothe right to relieve the pressure upon the facings of driven plate 23.

One of the problems encountered in such double disc clutches is therelease of the frictional contact of the facings of both driven discs.That problem has been solved as follows. A plurality of bolts 13 aredistributed about the clutch and extend through passages in bothpressure plates as shown. In plate 31 there is recess 15 within whichthe head I! of the bolt 13 is received. Each bolt has secured theretobetween the pressure] plates, a sleeve 19 and a coil spring 8| surroundsthe bolt and contacts the adjacent surfaces of the pressure plates tohold them apart when the clutch is released. The end of the bolt isundercut as at 83 and is engaged by a spring device 85 attached topressure plate 29 at 81. The dimension of the spring device is such thatthe bolt rump may be advanced toward the left so that the spring deviceengages and grips the bolt at new positions toward the right but thespring device holds the bolt from moving toward the right through plate29. When the clutch is engaged there is a little space between the headof the bolt 13 and the bottom wall of recess 15 as shown by Figure 5.

The operation of the mechanism associated with bolt 13 is as follows:

If the clutch is engaged under the influence of its spring 4| the partsare as shown in Figure 5. The spring has pushed pressure plate 31 to theleft and it has pushed the pressure plate 29 through theinstrurnentality of the facings on driven disc 23 so that the facings ofdriven disc 25 are gripped between the flywheel and pressure plate 29.All facings are effective to produce frictional resistance to slip. Itnow the clutch is released by withdrawing the throwout sleeve, plate 31is moved to the right by the movement of the spring 4| acting upon thebolt 69 as explained above. After a limited movement of plate 31 itpicks up the head of bolt 11 by engagement between the bottom of recess15 and said bolt head. Further movement of plate 31 pulls the pressureplate 29 positively away from the driven plate 25 because of the grip of85 on the bolt. The spring 8| maintains the desired spaced relation ofthe two pressure plates. The released position is shown by Figure 4. Inapplying the clutch the pressure plate 31, as explained above, not onlymoves pressure plate 29 through the facings 01' driven plate 23 but itdevelops a clearance at the bolt head and removes the clearance adjacentthe sleeve I9. If, by chance, the facings are reduced in thickness bywear a movement somewhat more than normal is required. Under thesecircumstances in the act of clutch engagement plate 31 pushes the boltby contact with the sleeve 19 and the spring 85 grips the bolt in itsnew position of adjustment. By the expedient described the normalclearance is always present avoiding the need of excessive clutch pedaltravel. The release is always positive avoiding any dragging of thefriction members. The construction is very simple and easily installed.

I claim:

1. In a clutch, a driving member, spaced first and second pressureplates rotatable therewith, spaced driven discs one adjacent the drivingmember and the other between the pressure plates, means to reciprocatesaid pressure plates, other means to automatically take up wear andincluding a part extending through said pressure plates, said parthaving enlargements on opposite sides of said first pressure plate andspaced to an extent greater than the thickness of said pressure plateand a one-way clutch device between said other means and said secondpressure plate.

2. In a clutch having a plurality of driven discs and a plurality ofpressure plates, means actuated by a releasing movement of one pressureplate to positively release a second pressure plate, said meansincluding a mechanism to compensate for wear, said means including abolt extending through axially aligned openings in said pressure plates,a head on said bolt and a sleeve secured to said bolt and locatedbetween said pressure plates in predetermined spaced relation to saidhead.

3. In a clutch having a plurality of driven discs and a plurality ofpressure plates, means actuated by a releasing movement of one pressureplate to positively release a second pressure plate, said meansincluding a mechanism to compensate for wear, said means including abolt extending through axially aligned openings in said pressure plates,a head on said bolt and a sleeve secured to said bolt and locatedbetween said pressure plates in predetermined spaced relation to saidhead and said mechanism comprising a spring device secured to one ofsaid pressure V plates and engaging said bolt whereby the bolt may movein one direction only relative to said last named pressure plate.

4. In a clutch. a flywheel, first and second axially spaced pressureplates, a first driven disc between the fiywheel and first pressureplate, a second driven disc between the first and second pressureplates, spring means to engage the clutch, means to overcome said springmeans and release the clutch, a bolt extending through registeringopenings in said pressure plates, a head on said bolt onthe side of thesecond pressure plate remote from the first pressure plate, abutmentmeans on said bolt between said pressure plates positioned to provide apredetermined relative axial movement between said bolt and secondpressure plate.

5. The invention defined by claim 4, together with means associated withsaid bolt and said first pressure plate whereby a relative movement inone direction only therebetween is provided.

6. The invention defined by claim 4, said bolt having an undercut regionon the part thereof on the flywheel side of the first pressure plate, aplate spring secured to 'the first pressure plate, said springdimensioned to be bent in assembly in a way to permit the bolt to movetoward the fiywheel but to hold it from movement through the firstpressure plate in the opposite direction whereby the clutch may bepositively released and whereby automatic compensation for wear may takeplace.

GEORGE HUNT.

